| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | Joseph Snipes |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| MP 316 Initial Active MHD TAE Experitments in Ohmic Plasmas. Snipes/Mar |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:31:100PM |
| Author: To Be Determined |
| Run Summary for Thursday 1021003 Initial Active MHD TAE Experiments in Ohmic Plasmas MP 316 Summary: It was a very good run where we achieved even more than the mini-proposal called for. TAE resonances were observed on most shots showing a factor of two increase above the background at 421 kHz. Resonances followed the TAE frequency formula in proportion to toroidal field and inversely with the sqrt of the density at least approximately. On some shots, the frequency of the resonance was spot on the formula using the line averaged density and BTOR toroidal field. We also showed on shot 1021003022 that we could still observe a TAE resonance down to 21 W of input power, which corresponds to nearly 3 A of current in the antenna. The last two shots (24 and 25) were done with diverted plasmas at high density and clear TAE resonances were observed on both shots at high triangularity and lower triangularity. The poloidal field amplitude measured at the AB limiter during the Active MHD antenna pulse at full power (400 W) was nearly 2 x 10^-6 T. Attempts were also made to sweep the frequency over the limited range where matching could be obtained on shots 16, 17, 19, and 21. The largest range corresponded to 421 kHz + 1% - 2% and some resonances were observed, though they appeared weak in the raw data. Further analysis is required to accurately determine damping rates. Initial estimates based on the TF ramps indicate a Q of about 40 or a damping rate of 2.5%, which is in the range observed on JET. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:16:440PM |
| Author: To Be Determined |
| Physop run summary 1021003 MP 316: Initial Active MHD TAE Experiments in Ohmic Plasmas Session leader: J. Snipes Physics operator: E. Marmar Power Systems as on 1021002021 except TF current limit set to 175 kA ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Run begins at 09:00 and ends at 17:00. Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC) fill C-side with 30 psi D2 Hybrid enabled (PG3) leave J-Bottom as is Hybrid DISABLED (PG5) Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: All 4 transmitters OFF throughout the run! Run Plan: Run Ohmic inner wall limited plasmas at low elongation (kappa < 1.4) and low triangularity (delta < 0.3) at 0.8 MA with TF ramp from 6 T at 0.6 s down to 3.5 T at 1.5 s at moderate density initially set to nl04 = 5.6 x 10^19 m^-2. Drive the Active MHD antenna at 350 - 400 W at matching frequency in the middle of the TAE range for q=1.5 for standard conditions, which is presently at 411 kHz. Look for TAE resonances on magnetic pick-up coils driven by the antenna as the plasma sweeps through the resonance. Vary the density shot to shot to look for the resonance. Depending on the results, current ramps may also be used to vary q95. If resonances are observed and time permits, go to helium plasmas to check the mass dependence of the TAE resonance. - The run went well. Good data were collected with the active MHD driving stable mode(s) (see session leader summary). We ran inner wall limited discharges over a range of densities (nl_04 from 6e19 to 2.3e19 in l-mode) and currents (.7 to 1.0 MA), with Bt sweeps, covering ranges from 7 Tesla to 3 Tesla over the course of the day. The last 2 plasmas (24 and 25) were diverted with TF ramps. Both showed the "weird" high-field ohmic H-mode-like behavior that we have seen in the past, with increases in density, decreases in D-alpha, increases in neutron rate, and no effect on the edge x-rays. Startup was reliable, with minor tweaks to prepuff and B_R0. A few shots had hard x-rays early; increasing the prepuff seemed to help. There was no between-shot ECDC today. Problems: Snipes lost his PCI data acquisition on shot 20, and it took about 80 minutes to get it back. Shot 23 was lost to a pulled breaker during check. Scorecard: Plasmas 23 Fizzle 1 Duds 0 tests/no power cycles 1 Total data cycles 25 From: SPANNA::MARMAR Date: 3-OCT-2002 17:57:52 Subj: Physop run summary 1021003 Physop run summary 1021003 MP 316: Initial Active MHD TAE Experiments in Ohmic Plasmas Session leader: J. Snipes Physics operator: E. Marmar Power Systems as on 1021002021 except TF current limit set to 175 kA ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Run begins at 09:00 and ends at 17:00. Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC) fill C-side with 30 psi D2 Hybrid enabled (PG3) leave J-Bottom as is Hybrid DISABLED (PG5) Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: All 4 transmitters OFF throughout the run! Run Plan: Run Ohmic inner wall limited plasmas at low elongation (kappa < 1.4) and low triangularity (delta < 0.3) at 0.8 MA with TF ramp from 6 T at 0.6 s down to 3.5 T at 1.5 s at moderate density initially set to nl04 = 5.6 x 10^19 m^-2. Drive the Active MHD antenna at 350 - 400 W at matching frequency in the middle of the TAE range for q=1.5 for standard conditions, which is presently at 411 kHz. Look for TAE resonances on magnetic pick-up coils driven by the antenna as the plasma sweeps through the resonance. Vary the density shot to shot to look for the resonance. Depending on the results, current ramps may also be used to vary q95. If resonances are observed and time permits, go to helium plasmas to check the mass dependence of the TAE resonance. - The run went well. Good data were collected with the active MHD driving stable mode(s) (see session leader summary). We ran inner wall limited discharges over a range of densities (nl_04 from 6e19 to 2.3e20 in L-mode) and currents (.7 to 1.0 MA), with Bt sweeps, covering ranges from 7 Tesla to 3 Tesla over the course of the day. The last 2 plasmas (24 and 25) were diverted with TF ramps. Both showed the "weird" high-field ohmic H-mode-like behavior that we have seen in the past, with increases in density, decreases in D-alpha, increases in neutron rate, and no effect on the edge x-rays. Startup was reliable, with minor tweaks to prepuff and B_R0. A few shots had hard x-rays early; increasing the prepuff seemed to help. There was no between-shot ECDC today. Problems: Magnetics PCI data acquisition went awry on shot 20, and it took about 80 minutes to get it working. Shot 23 was lost to a pulled breaker during check. Scorecard: Plasmas 23 Fizzle 1 Duds 0 tests/no power cycle 0/1 Total data cycles 25 |
| Session Leader Comments | |||
| Oct 3 2002 09:08:08:677AM | 1021003001 | Joseph Snipes | Start with WAVEFORM for External Control of the ENI off to give a reference plasma. Disrupted at 1.28 s for no obvious reason. Perhaps, something fell into the plasma. |
| Oct 3 2002 10:19:20:947AM | 1021003002 | Joseph Snipes | Shot 2: External control at 3.8 V. F0 = 421 kHz, HPFG = 0.488 V. Got 140 W. Disrupted at 1.21 s. |
| Oct 3 2002 10:43:35:490AM | 1021003003 | Joseph Snipes | Shot 3: Raised Ext. Control to 5 V. |
| Oct 3 2002 10:20:03:793AM | 1021003004 | Joseph Snipes | Shot 4: Weak resonance in the current rise at about 0.13 s on BP03_ABK. |
| Oct 3 2002 10:20:14:653AM | 1021003005 | Joseph Snipes | Shot 5: Weak resonance in the current rise at about 0.13 s on BP03_ABK. |
| Oct 3 2002 10:39:15:830AM | 1021003006 | Joseph Snipes | Shot 6: Doubled the density. Resonance at 1.2 s on BP03_ABK. |
| Oct 3 2002 10:44:00:770AM | 1021003008 | Joseph Snipes | Shot 8: Raised Ext. Control to 9 V. |
| Oct 3 2002 11:02:32:787AM | 1021003008 | Joseph Snipes | Shot 8: Raised Ext. Control to 9 V. Intermediate density. Resonance at 1.3 s. |
| Oct 3 2002 11:20:29:160AM | 1021003009 | Joseph Snipes | Shot 9: Raised Ext. Control to 10 V. Lower density to 7.5 x 10^19 m^-2. |
| Oct 3 2002 11:31:56:590AM | 1021003010 | Joseph Snipes | Shot 10: Raised density to 1.5 x 10^20 m^-2. Resonance moved to 0.8 s. The resonance is clearly following the TAE formula. |
| Oct 3 2002 11:56:29:013AM | 1021003011 | Joseph Snipes | Shot 11: Raised density to 1.7 x 10^20 m^-2. Resonances appear at 0.35 and 0.45 s. |
| Oct 3 2002 12:14:07:013PM | 1021003012 | Joseph Snipes | Shot 12: Raise Ip to 0.85 MA and Bt to 6.9 T to be able to sustain nearly this high a density. Disrupted at 1.7 s. Nice resonance at 1.15 s. |
| Oct 3 2002 12:17:53:453PM | 1021003012 | Joseph Snipes | Shot 12: Raise Ip to 0.85 MA and Bt to 6.9 T to be able to sustain nearly this high a density. Disrupted at 1.7 s. Nice resonance at 1.15 s. Resonant frequency agrees spot on at 421 kHz with the nebar calculation at RMAGX. |
| Oct 3 2002 12:42:16:020PM | 1021003013 | Joseph Snipes | Shot 13: Raise density by 10%. Nice resonance at 1.05 s |
| Oct 3 2002 12:49:06:657PM | 1021003014 | Joseph Snipes | Shot 14: Raise density to nl04 = 2.2 x 10^20 m^-2. Resonance at 0.82 s. |
| Oct 3 2002 01:09:12:107PM | 1021003015 | Joseph Snipes | Shot 15: Raise density to nl04 = 2.3 x 10^20 m^-2. |
| Oct 3 2002 01:54:44:783PM | 1021003016 | Joseph Snipes | Shot 16: Slow ramp in BT from 5.8 to 5.6 T at nl04 = 1.5 x 10^20 m^-2. Turned on VCO to sweep the frequency by 2% about 421 kHz for 5 sweeps. Brief resonance. |
| Oct 3 2002 01:56:10:173PM | 1021003017 | Joseph Snipes | Shot 17: Flat Bt at 5.8 T, nl04 = 1.7e20 m^-2. Got a brief resonance again but not very clear. |
| Oct 3 2002 01:56:24:283PM | 1021003018 | Joseph Snipes | Shot 18: Fizzle! |
| Oct 3 2002 03:58:01:533PM | 1021003019 | Joseph Snipes | Shot 19: Slight ramp in TF with VCO at +1 - 3% of F0 = 421 kHz. |
| Oct 3 2002 04:00:43:317PM | 1021003020 | Joseph Snipes | Shot 20: Good shot, but lost ACQ16 data. Long delay to recover proper operation of the ACQ16. Needed to reboot PCDAQ1 then TCL STOP SERVER DAQA::MHDA_DAQ_SERVER ssh pcdaq1 -l dt100 dt100 acqcmd setChannelMask 1111111111110000 |
| Oct 3 2002 04:14:12:093PM | 1021003021 | Joseph Snipes | Shot 21: Repeat to get ACQ16 data. Got the sweep, but the resonance is not so clear. |
| Oct 3 2002 04:29:28:357PM | 1021003022 | Joseph Snipes | Shot 22: Repeat shot 10 at external control = 0.7 V to see if we can still see a resonance at low power. Turned off VCO. Clear resonance with only 21 W of ENI power! |
| Oct 3 2002 04:33:52:657PM | 1021003023 | Joseph Snipes | Shot 23: Attempted to reproduce similar conditions to shot 22 with a diverted plasma but a breaker pulled so there were no power supplies. |
| Oct 3 2002 05:28:05:493PM | 1021003024 | Joseph Snipes | Shot 24: Repeat the diverted shot. Got a resonance at around 1 s. |
| Oct 3 2002 05:30:17:760PM | 1021003025 | Joseph Snipes | Shot 25: Repeat the diverted shot at lower triangularity. Got a resonance at around 0.8 - 1 s that is very clear. |
| Oct 3 2002 05:44:26:177PM | 1021003025 | Joseph Snipes | Summary: It was a very good run where we achieved even more than the mini-proposal called for. TAE resonances were observed on most shots showing a factor of two increase above the background at 421 kHz. Resonances followed the TAE frequency formula in proportion to toroidal field and inversely with the sqrt of the density at least approximately. On some shots, the frequency of the resonance was spot on the formula using the line averaged density and BTOR toroidal field. We also showed on shot 1021003022 that we could still observe a TAE resonance down to 21 W of input power, which corresponds to nearly 3 A of current in the antenna. The last two shots were done with diverted plasmas at high density and clear TAE resonances were observed on both shots at high triangularity and lower triangularity. |
| Physics Operator Comments | |||
| Oct 3 2002 08:57:59:307AM | Earl Marmar | MP 316: Initial Active MHD TAE Experiments in Ohmic Plasmas Session leader: J. Snipes Physics operator: E. Marmar Power Systems as on 1021002021 except TF current limit set to 175 kA ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Run begins at 09:00 and ends at 17:00. Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC) fill C-side with 30 psi D2 Hybrid enabled (PG3) leave J-Bottom as is Hybrid DISABLED (PG5) Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: All 4 transmitters OFF throughout the run! Run Plan: Run Ohmic inner wall limited plasmas at low elongation (kappa < 1.4) and low triangularity (delta < 0.3) at 0.8 MA with TF ramp from 6 T at 0.6 s down to 3.5 T at 1.5 s at moderate density initially set to nl04 = 5.6 x 10^19 m^-2. Drive the Active MHD antenna at 350 - 400 W at matching frequency in the middle of the TAE range for q=1.5 for standard conditions, which is presently at 411 kHz. Look for TAE resonances on magnetic pick-up coils driven by the antenna as the plasma sweeps through the resonance. Vary the density shot to shot to look for the resonance. Depending on the results, current ramps may also be used to vary q95. If resonances are observed and time permits, go to helium plasmas to check the mass dependence of the TAE resonance. | |
| Oct 3 2002 09:15:34:037AM | 1021003001 | Earl Marmar | loading shot set up by Joe Snipes Segment 1 from 1021002025 increase prepuff to 25 msec (early in run, DNB GV opening) Segment 2: start from 1010627010 decrease Ip to 800kA Ramp field, first up, then down fiddle with shape plasma disrupt at 1.29 started getting dirty and resistive at about 1.13; not obvious why |
| Oct 3 2002 09:29:14:757AM | 1021003002 | Earl Marmar | move zxl down move zcur up start TF rampdown 50 msec earlier plasma disrupt at 1.21 s (density is dropping, radiation increases) |
| Oct 3 2002 09:42:13:347AM | 1021003003 | Earl Marmar | reduce clearin (1 cm more negative) to reduce elongation plasma disrupt at 1.12 |
| Oct 3 2002 10:27:28:187AM | 1021003004 | Earl Marmar | reduce clearin 1 more cm reduce Ip to 750 kA plasma made it all the way through this time q_95 gets down to 2.97 early hards; bounced during current rise |
| Oct 3 2002 10:10:51:633AM | 1021003005 | Earl Marmar | add 1 msec to prepuff still early hards disrupt at 1.28 |
| Oct 3 2002 10:24:54:023AM | 1021003006 | Earl Marmar | add 2 msec to prepuff nl_04 to 1.2e20 plasma lumpy rampdown, but otherwise a good shot |
| Oct 3 2002 10:43:20:473AM | 1021003007 | Earl Marmar | nl_04 to 9e19 plasma good shot |
| Oct 3 2002 10:50:10:197AM | 1021003008 | Earl Marmar | decrease prepuff by 1 msec plasma good shot |
| Oct 3 2002 11:11:58:667AM | 1021003009 | Earl Marmar | decrease nl_04 to 7.5e19 plasma good shot |
| Oct 3 2002 11:37:24:313AM | 1021003010 | Earl Marmar | nl_04 up to 1.5e20 plasma disrupt in rampdown at 500 |
| Oct 3 2002 11:53:41:373AM | 1021003011 | Earl Marmar | nl_04 to 1.7e20 plasma resistive and disruptive; couldn't take the density finally dies at 0.7 seconds |
| Oct 3 2002 12:15:31:513PM | 1021003012 | Earl Marmar | go to 7 Tesla early; then ramp down Ip program to 850 kA nl_04 to 1.6e20 plasma; good shot |
| Oct 3 2002 12:20:45:550PM | 1021003013 | Earl Marmar | nl_04 to 1.75e20 plasma; good shot |
| Oct 3 2002 12:44:31:130PM | 1021003014 | Earl Marmar | nl_04 to 2.2e20 Ip to 1.0 MA plasma; good shot all the oh power supplies are hitting their rails between 1.2 and 1.4 seconds; the current starts to ramp down at 1.38 seconds; disrupt at 1.5 s, 800 kA |
| Oct 3 2002 01:15:46:470PM | 1021003016 | Earl Marmar | Bt up to 5.8T, then slow ramp to 5.6 nl_04 to 1.5e20 Ip to 800 kA plasma; good shot small density increase shortly after 1 second (marfe moving?) |
| Oct 3 2002 01:49:32:247PM | 1021003017 | Earl Marmar | Bt flat at 5.8T nl_04 to 1.7e20 plasma; good shot |
| Oct 3 2002 01:53:21:157PM | 1021003018 | Earl Marmar | Bt ramp down from 5.90 to 5.60 Tesla fizzle |
| Oct 3 2002 02:13:49:283PM | 1021003019 | Earl Marmar | reduce prefill by 2 msec reduce B_R0 offset by .5 mT plasma Early hards; otherwise seems fine |
| Oct 3 2002 02:41:30:850PM | 1021003020 | Earl Marmar | add 2 msec to prepuff reduce Bt by 0.1 tesla, still ramping down during shot plasma good shot |
| Oct 3 2002 04:05:31:227PM | 1021003021 | Earl Marmar | after long delay to fix pci data acquisition no PCS changes plasma good shot |
| Oct 3 2002 04:37:30:500PM | 1021003022 | Earl Marmar | reload segment 2 from 1021003010 plasma good shot |
| Oct 3 2002 04:37:55:020PM | 1021003023 | Earl Marmar | breaker pulled during check --> no power cycle |
| Oct 3 2002 05:47:35:807PM | 1021003024 | Earl Marmar | load segment 2 from 1021001014 copy nl_04, toroidal field, Ip waveforms from 1021003022, segment 2 (attempting diverted shot with TF scan) plasma; good shot weird H-mode-like behavior starting at .611s (6 Tesla) density doubles, D-alpha drops, neutron rate goes up a factor of 4, edge x-rays don't budge |
| Oct 3 2002 05:17:30:000PM | 1021003025 | Earl Marmar | move RXL out by 2 cm (reduce delta_lower) increase B_R0 by 0.5 mT plasma; good shot weird H-mode-like behavior starting at 0.813 s (5.7 Tesla) density nearly doubles, D-alpha drops, neutrons go way up, edge x-rays don't budge |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:57:12:823AM | Plasma | Ok | |
| 2 | 09:15:14:537AM | Plasma | Ok | |
| 3 | 09:29:47:740AM | Plasma | Ok | |
| 4 | 09:46:33:593AM | Plasma | Ok | |
| 5 | 10:00:21:500AM | Plasma | Ok | |
| 6 | 10:15:08:097AM | Plasma | Ok | |
| 7 | 10:31:16:897AM | Plasma | Ok | |
| 8 | 10:45:06:020AM | Plasma | Ok | |
| 9 | 11:03:23:973AM | Plasma | Ok | |
| 10 | 11:18:01:657AM | Plasma | Ok | |
| 11 | 11:35:29:157AM | Plasma | Ok | |
| 12 | 11:59:53:313AM | Plasma | Ok | |
| 13 | 12:17:23:670PM | Plasma | Ok | |
| 14 | 12:32:31:400PM | Plasma | Ok | |
| 15 | 12:50:31:407PM | Plasma | Ok | |
| 16 | 01:09:36:873PM | Plasma | Ok | |
| 17 | 01:32:25:970PM | Plasma | Ok | |
| 18 | 01:50:50:513PM | Plasma | Ok | |
| 19 | 02:04:28:883PM | Plasma | Ok | |
| 20 | 02:27:35:637PM | Plasma | Ok | |
| 21 | 03:56:19:267PM | Plasma | Ok | |
| 22 | 04:15:57:063PM | Plasma | Ok | |
| 23 | 04:31:12:810PM | Plasma | Bad | pf breaker opened just prior to the shot |
| 24 | 04:48:25:680PM | Plasma | Ok | |
| 25 | 05:07:43:730PM | Plasma | Ok | |